Seizures can happen when there is damage to the gray matter of the brain. This gray matter is called the(cortex). Changes occuring in the connections of the cells of the damaged cortex when it is damaged can result in rare acute seizures or can give rise, after some time, to chronic epilepsy(many seizures over time).
Such damage can be from head injuries, which are the commonest cause of seizures in teen-agers and young patients. Surgery to the brain can be considered another type of injury. The more severe the injury, the more likely are seizures to happen. The chances for seizure following a concussion are relatively small(less than 5%) but if the skull is fractured or there is bleeding into brain(contusion) or if there is bleeding around the brain the likelihood of seizures increases upto about almost 50%. The longer coma lasts, the more severe is the injury and the greater the risk of seizures.The seizures can occur weeks or months or even years after the injury and can be few, or many and permanent.
Sometimes, relatively rarely, damage to brain by injury(trauma) or stroke produces seizures immediatly or very soon, within one to two weeks after the injury.
Such seizures are often associated just with the electric currents of injury and are temporary - they usually do not recurr.
Early seizures can result in later epilepsy, though this is not frequent.
Similar findings hold good with seizures after stroke. For example after stroke only about 6-7% of patients have seizures. Early seizures do not also mean late seizures in most patients. Late seizures(after a month) do mean that seizures are likely to recurr.
Infections of the membranes surrounding the brain, (meningitis,) may injure the cortex and cause seizures to develop and to persist.
Seizures can also be caused by infections of the brain, such as encephalitis( inflammation of the brain substance itself), most usually viral, or by brain abscess (which is a collection of pus in one place in the brain, rather like a large pimple or boil) or even by parasites living or dying in the brain.Brain abscess may occur after untreated ear infection, sinusitis, blood infections(septicemia) or lung infections including TB.
In the so-called underdeveloped lands the commonest causes of epilepsy are brain injury or parasites such as cysticercosis, hydatid disease among many others.
Very high fever(above 107 degrees Fahrenheit) can occur with infections especially in children or babies and can cause brain injury with seizures as a possible outcome.
Many drugs can provoke seizures in those who have a tendency to seizures and also in some people who may never have had a seizure before.
The drugs most commonly associated with seizures are:
1. many antihistamines
2. many of the drugs used for asthma treatment
3. many drugs used by psychiatrists for depression or for psychosis
4. many other individual drugs
Search the Physicians Desk Reference for these effects or discuss whether a new drugs may cause seizures with your treating doctor or neurologist.
Seizures are seen with many types of organ failure such as liver failure, kidney failure, or with abnormalities of calcium, magnesium regulation, or with salt and electrolyte(salt, potassium, chlorine, acid/ base, and water regulation) problems.
Other causes of metabolic disorder that can cause seizures include many endocrine(glands that put their chemicals directly into the blood) disorders including diabetes, thyroid, parathyroid, adrenal, piuitary gland disorders. Many poisons or drugs which alter these systems can provoke seizures.
The generalized epilepsies have a substantial inherited component - these include petit mal(generalized absense), generalized Grand mal(Tonic-clonic) epilepsy amongst others.
The other major types of epilepsy namely the acquired forms are more related to brain injury of one type or another. But even here there seems to be a small component of inherited liability or tendency. For instance family memebers of some of these patients may have a tendency to seizures.
There are several types of epilepsy which occur in children or babies which have a substantial inheritance factor.
Although the inherited types of epilepsy tend to have generalized seizure types for the most part, there are a few special types which are inherited and also partial or focal - for example, benign rolandic(central) epilepsy or benign occipital epilepsy.
Myoclonic epilepsies are those with myoclonus as part of the picture. Myoclonus consists of single jerks of any part of the body. Several of these are inherited in that the underlying disorder is inherited and is a disturbance of some chemical process in the cells. The cells degenerate and seizures are part of the picture especially myoclonus. Of course there are types of myoclonus that are not epileptic or even abnormal. For instance, hiccup is a kind of myoclonus and so are the jerks that occur in normal people on falling asleep.
On the other hand seizures are often precipitated or triggered by loss of sleep. Seizures can be precipitated in epileptic patients and also in some people, who do not have seizures but have an inherited tendency to seizures. Sleeping much less than usual is a fairly common trigger for seizures and should be avoided by patients with seizures or a tendency to seizures wherever possible. The usual causes of loss of sleep include college exams, too much partying, a new baby, work-shift changes, late-night TV viewing amongst the many possibilities.
Gradual reduction of the drug does not usually lead to the same result.
These seizures are not likely to recurr unless the circumstances repeat themselves(sudden stopping of drug or alcohol again) so these seizures do not often mean a permanent state of having seizures - called 'epilepsy' or 'seizure disorder'.
Any of the drugs that cause sleep( such as the barbiturates) or any of the major tranquillizers(such as the benzodiazepines) can cause such seizures if stopped suddenly.
There are many other parasites which can lodge in brain and cause seizures such as schistosomiasis(from swimming in infected water), hydatid disease(dog tape worm), amongst many others. These are all treata